1. Field of the Invention
This invention relates to new polyoxyalkylene derivatives which possess an excellent thickening property and to the preparation of such polyoxyalkylene derivatives. These products are useful as stable thickening agents for use in hydraulic fluids, textile printing emulsions, cosmetic emulsions, aqueous pigment suspensions and other emulsified or dispersed systems.
2. Description of the Prior Art
Polymeric water-soluble thickening agents are widely used for many purposes. Commercially-available polymeric thickeners differ widely in chemical composition. The diversity of available thickening agents is an indication that not all are equally useful. It is not unusual to find some thickening agents which perform well in a certain environment and not at all in another. In fact, in some uses no one thickening agent is completely satisfactory and there is a continual need and a continuing search for new thickening agents to satisfy many unmet needs. For instance, various cellulose derivatives or other water-soluble polymers such as sodium polyacrylates, polyacrylamides and polyethylene glycol fatty acid diesters are representative thickening agents. The polyethylene glycol fatty acid diesters are widely used for textile printing emulsions, cosmetic emulsions and aqueous pigment suspension. These esters suffer from the defect that they are not resistant to hydrolysis in an acid or alkaline medium so that under such conditons, the thickening effect initially obtained is gradually reduced.
Polyoxyalkylene compounds, including high molecular weight materials, are well known for use as surface-active agents as disclosed in U.S. Pat. No. 2,674,619. These compositions can be prepared at high molecular weights, for instance, up to 25,000 for use as aqueous thickeners. It is known that liquid polyoxyalkylene can be obtained by utilizing a mixture of ethylene oxide and another lower alkylene oxide in an oxide ratio of 75 to 90 percent ethylene oxide and 10 to 25 percent other lower alkylene oxides such as propylene oxide as taught in U.S. Pat. No. 2,425,755.